The present invention relates to bookmaking apparatuses that apply adhesive to side edges of a series of sheets aligned to form a bundle and bind them together with a cover sheet, and image forming systems that sequentially stacks sheets printed by an image forming apparatus that uses a bookmaking apparatus, applies adhesive to a side edge of sheets, and binds the sheets to a cover sheet to form a booklet. More particularly, the present invention relates to a bookmaking apparatus that effectively starts up from a cold start, or when restarting after the apparatus has been stopped.
Generally, these types of apparatuses are widely used as end devices of image forming apparatuses such as printers or copiers, and as bookmaking systems that bind a side of sheets formed with images to a cover sheet after stacking the sheets in page order and forming a bundle, and dispensing adhesive to that side. A variety of apparatus have been proposed that print predetermined information and at the same time automatically bind sheets, as an on-demand printing system, particularly recently in electronic publication.
As an example of such a system, Japanese Patent Publication No. 2004-209869 discloses one that automatically finishes a booklet of sheets output from an image forming apparatus as the latter system apparatus. According to that document, sheets output from an image forming apparatus are received from that discharge outlet and guided to the discharge path, then stacked in a tray provided at a downstream side of the discharge path. The sheet bundle stacked on the tray in a substantially horizontal posture are turned 90 degrees and guided to an adhesive application position in a vertical posture for the application of adhesive. An apparatus that folds and binds a sheet bundle applied with adhesive together with a cover sheet supplied from an inserter provided at a discharge path to bind them is disclosed.
For example, in the system disclosed by Japanese Patent Publication No. 2004-209869 to apply adhesive to a sheet bundle held in a vertical posture by gripping means, a container holding adhesive is provided, and a roller arranged in the container, covered with adhesive travels along the side edge of the sheets to apply adhesive to the bottom edge of the sheets. Thermo-fusion (or hot melt) adhesive is used as the adhesive. This type of adhesive is in a solid form until it is placed in the container, and is easy to handle. After it is placed in the container, it melts into a liquid form for application to the sheet bundle. After application, it hardens and becomes fixed to the sheet bundle. In apparatus that use this kind of thermo-fusion adhesive, the apparatus is operable after the adhesive in the container is heated by heating means (such as a heater embedded in the container that stores adhesive) to a predetermined melting temperature.
In a bookmaking apparatus that uses thermo-fusion adhesive, a warming-up operation may be performed while reheating adhesive that is hardened in the container to a predetermined position temperature, such as when the apparatus is started or restarted after trouble such as a paper jam has occurred. The purpose of such a warming-up operation, i.e., receiving sheets in a stacking tray, is to allow plenty of time for the adhesive in the container to completely reach a predetermined melting temperature so that the degree of adhesive melting does not vary according to the ambient temperature of the apparatus, the amount of adhesive in the container, or the degree of solidification of the adhesive.
Therefore, the execution of operations such as the setting of operating modes, printing processes and the stacking of sheets into bundles is possible after the apparatus has passed a warming up time. For example, in a system that links a bookmaking apparatus to a discharge outlet of an image forming apparatus, the remaining adhesive in the container is melted at the same time as the image forming unit is initializing and the apparatus detects any sheets remaining in the sheet conveyance path, and after everything is prepared for operation, operations are executed in the order of printing, stacking sheets in a bundle, and gripping and conveying the sheet bundle to the adhesive application position. For that reason, if time is required to melt the adhesive in the container, the sheet stacking unit and the image forming unit at an upstream side of the adhesive application position are placed at an idling state. As time is required in melting remaining adhesive, productivity of the system is an issue.
An object of the present is to provide a bookmaking apparatus that can improve the operating rate of the apparatus as a system by executing upstream sheet bundle stacking and image forming operations while melting adhesive when starting up the apparatus.